San Juan River (Colorado River)

The San Juan River is a major tributary of the Colorado River in the American Southwest, providing for the chief drainage of the Four Corners region of Colorado, New Mexico, Utah, and Arizona. It flows 383 miles through the deserts of northern New Mexico and southeastern Utah to join the Colorado River at Glen Canyon, and, while it is one of the muddiest rivers in North America, it is the only significant source of fresh water for many miles.